Data Management Plan

Photoscience completed the original collection and classification of the multiple return LiDAR of Charleston County, South Carolina in the winter of 2006-2007. In 2009, Sanborn collected portions of Charleston County which were previously uncollected in 2006/7. In 2013, Dewberry was tasked with reviewing, updating and merging the original LiDAR products into one continuous data to include the 2006-2007 and 2009 separate projects. The 2006/2007 data was separated from the 2009 collected points in order to keep the 2 missions separate (collection dates, standards, data qualities, etc). The 2006-2007 data was removed by analyzing GPS time stamps of the LAS points in order to differentiate by collection year. The resulting LAS files left only the 2009 points which represent this project. The 2007 data already exists at OCM as part of a previous delivery. The nominal point spacing for this project is 1.4 meters. Dewberry used proprietary procedures to update and reclassify the LAS according to updated project specifications: 1-Unclassified, 2-Ground, 7-Noise, 8- Model Key Points, 9-Water, 10-Ignored Ground, 13- Points removed from bridges and culverts.

Process Steps:

• 2007-03-23 00:00:00 - JASPER COUNTY: Utilizing Photo Science's two ALS-50 LiDAR sensors, data was collected to cover Jasper County, South Carolina. Data was collected in a total of 111 flightlines at a pulse rate of 75,000 points per second. COLLETON COUNTY: Utilizing Photo Science's two ALS-50 LiDAR sensors, data was collected to cover Colleton County, South Carolina. Data was collected in a total of 160 flightlines at a pulse rate of 75,000 points per second. CHARLESTON COUNTY: Utilizing Photo Science's two ALS-50 LiDAR sensors, data was collected to cover Charleston County, South Carolina. Data was collected in a total of 77 flightlines at a pulse rate of 75,000 points per second. Originally collected from 20061227 through 20070323.
• 2007-10-30 00:00:00 - Raw LiDAR data (collected as Process Step 1) was processed to create a bare ground surface. Process included calibration of LiDAR data to remove systematic errors (utilizing Leica's ALS Processor software), adjustment of elevation data to control positions (utilizing TerraScan software for control comparisons and adjustments), and both automatic and manual editing to correctly classify ground and non-ground data (utilizing TerraScan and TerraModeler software). In addition, QC steps were performed before and after processing. QC steps included line-to-line vertical comparisons and coverage checks, and were performed with TerraScan and GeoCue software.
• 2009-01-01 00:00:00 - The ABGPS, IMU, and raw Leica ALS-50 LiDAR data are integrated into the LEICA ALS post processor software. The resultant file is in a LAS binary file format. The LAS file version 1.2 formats can be easily transferred from one file format to another. It is a binary file format that maintains information specific to the LiDAR data (return#, intensity value, xyz, etc.). The resultant points are produced in the geodetic coordinates referenced to the NAD83 horizontal datum and GRS80 vertical datum. The date and time for each flight line can be determined using the Julian date and time.
• 2009-01-01 00:00:00 - The unedited data are classified to facilitate the application of the appropriate feature extraction filters. A combination of proprietary filters is applied as appropriate for the production of bare earth digital terrain models (DTMs). Interactive editing methods are applied to those areas where it is inappropriate or impossible to use the feature extraction filters, based upon the design criteria and/or limitations of the relevant filters. These same feature extraction filters are used to produce elevation height surfaces. The LiDAR mass points were delivered in American Society for Photogrammetry and Remote Sensing LAS 1.2 format. The header file for each dataset is complete as define by the LAS 1.2 specification. In addition the following fields are included: Flight Date Julian, Year, and Class. The LAS files do not include overlap. The data was classified as follows: 1-Unclassified, 2-Ground, 7-Noise,8- Model Key Points, 9-Water, 10-Ignored Ground, 13- Points removed from bridges and culverts.
• 2009-01-01 00:00:00 - Conversion from Geodetic coordinates NAD83 into State Plane coordinates (International Feet) NAD83 and conversion from ellipsoid heights (meters) into orthometric heights (U.S. Survey Feet).
• 2014-01-01 00:00:00 - Dewberry updated the horizontal datum for the 2009 data from NAD83 to NAD83 (NSRS2007) and the vertical datum from NAVD88 (Geoid03) to NAVD88 (Geoid09). The projection and all units remain the same. Additionally, Dewberry updated the precision of the lidar data from 2 decimal places to 3 decimal places. Dewberry also reviewed the LiDAR data and removed gross artifacts and anomalies by re-classifying the LiDAR points to more appropriate classes.
• 2014-06-02 00:00:00 - The NOAA Office for Coastal Management (OCM) received the files in laz format via hard drive from Dewberry. The data arrived referenced to the South Carolina State Plane (3900) and vertical reference to NAVD88 elevation in feet: 1. The data were converted from projected orthometric coordinates to geographic coordinates. 2. Vertical values were converted from NAVD88 to ellipsoidal values using Geoid09. 3. The 2006/2007 data was separated from the 2009 collected points in order to keep the 2 missions separate (collection dates, standards, data qualities, etc). The 2007 data was removed by analyzing time stamps for each point in the LAS files in order to differentiate collection year. The resulting LAS files showed only the 2009 points. The 2007 data already exists at OCM as part of a previous delivery. 4. The LAS data were stored as compressed LAZ data.

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=3653

The data set is dynamically generated based on user-specified parameters.;